Apparatus for the restraint and control of oxygen lances



March 13, 196 K. REINFELD ET AL APPARATUS FOR THE RESTRAINT AND CONTROLOF OXYGEN LANCES 2 Sheets-Sheet 1 Filed Oct. 11, 1960 INVENTORS.ETC/I420 F. aes/vcwnz xuer EEINF'ELD. BY

2 Sheets-Sheet 2 QQOQP M.

their a 'rraP March 13, 1962 K. REINFELD ET AL APPARATUS FOR THERESTRAINT AND CONTROL OF OXYGEN LANCES Filed Oct. 11, 1960 United.htates Patent @Hice 3,@Z5,M7 Patented Mar. 13, 1.962

Deiaware Filed Get. 11, 1960, Ser. N 61351 3 Claims. (Ci. 266--34) Thisinvention relates to apparatus for an oxygen steelmaking converter, andmore particularly, to apparatus for supporting a lance for supplyingoxygen for such a converter.

It is typical in the art to use a long tube or lance to force oxygeninto contact with the surface of molten pig iron in an oxygen converteras is required in conventional steelmaking to eliminate certain chemicalelements (silicon, manganese, sulfur, carbon and phosphorus) from thepig iron. The lance is usually inserted through an opening in the upperend of a closed bottom converter, and a high velocity jet ofsubstantially pure oxygen is forced downwardly against the surface ofthe molten metal in the converter from an orifice at the end of thelance.

By ejecting the oxygen at velocities in the transonic and supersonic ranes (velocities of Mach 2 are common) the effect is to cause this oxygento strike the surface of the bath and initiate reactions with themetalloid impurities. These reactions in turn violently agitate thebath.

The violent agitation of the bath is due to the temperature and densitydifferentials between that portion of the bath surface under the oxygenjet (primary reaction area) and the rest of the bath. In the reactionzone, temperatures close to the boiling point of iron prevail. Also, theevolution of CO is strongest in the immediate vicinity of this reactionzone. As a result, the froth and gases in the converter above thesurface of the bath are in a whirling turbulence. It is to be expected,as is in fact the case, that under the combined influences of thereaction from the ejected oxygen blast and the buffeting action of thechurning gases in the converter, the lance will be subjected to forcestending to produce violent rotating and rocking actions in the lance.These actions induce such severe vibrations in the lance as to pose theproblem of supporting the lance so as to oppose these forces andminimize the vibrations whereby to effectively restrain and control thelance during the blowing operation.

Effective control of the lance during the blowing operation is desirableto permit accurate positioning of the lance with reference to thesurface of the molten metal.

This positioning is ditlicult, however, because the level of the metalin the converter and the chemical analysis of the metal vary. Inresponse to these fluctuating conditions, frequent changes in thepositioning of the lance become necessary during each oxygen blowingperiod.

Apparatus for positioning and restraining the lance heretofore hasconsisted of a Wire rope hoisting device, a lance guide, and a clamp.The lance guide and the clamp are generally mounted on the top of thehood above an opening therein. Alternatively, they have been mounted onsome structure adjacent the converter but completely independent of thelance itself as in the case of the hood-mounted clamp. Since the lancehas a Water jacket thereabout and has hoses leading therefrom, theeccentric force of these attachments to the lance prevent the lance fromhanging with the axis of the lance vertical. Therefore, in operation,the wire rope hoisting device lowers the eccentrically supported lanceuntil the tip of the lance is engaged with the lance guide whichpositions the end of the lance for passage through the opening in thehood and, once properly guided, the lance is lowered to the desiredposition. Then the hoodrnounted clamp is closed about the lance tosupport and restrain it positioning the orifice of the lance at thedesired distance above the surface of the bath. As often as or moretimes per day during the oxygen blowing periods it becomes necessary tochange the relative position between the lance nozzle orifice and thetop of the bath, each time requiring the engagement and disengagement ofthe hood-rnounted clamp.

Unfortunately, during the repositioning of the lance, the high velocityoxygen input must, of necessity, be reduced considerably or completelyshut off since during this period the lance is substantiallyunrestrained against vibration. Thus, each time the hood-mounted clampis released and then reengaged, the blowing operation is interruptedcausing the timewise extension of this operation and resulting in amarked decrease in efficiency.

An added disadvantage is that the openin and closing of the hood-mountedor otherwise independently mounted clamp for each lance adjustment plusthe maintenance occasioned by frequently occurring clamp failures alsorestrict the availability of the converter vessel itself for the blowingoperations.

Although some devices heretofore have mounted clamps on structure otherthan the hood, in no case is the clamp so arranged as to continuouslyaccompany the lance sup porting it through the repositioning thereof toobviate reduction of the oxygen blast.

Also, any clamping or guiding devices placed at the top of the hood mustbe cleared by the lance when it is withdrawn for charging or tapping.Therefore, the height of the building housing the converter operationsmust be increased in turn by the height of such clamping or guidingdevices, a height of as much as 5 feet. The great expense occasionedthereby is a distinct drawback to the use of such an arrangement.

it is therefore, an object of this invention to provide an improvedmeans for restraining and controlling the positioning of an oxygenlance.

It is another object of this invention to provide a guiding andrestraining device for an oxygen lance to permit oxygen flow from thelance at full capacity throughout the oxygen blowing operation.

An additional object of this invention is to provide lance-handlingequipment enabling a reduction in the height of the building required tohouse an oxygen steelmaking operation.

Still another object of this invention is to provide a device for therestraint and control of an oxygen lance in which the maintenanceproblem will be eliminated or greatly reduced.

This invention provides a novel apparatus for continuously restrainingand controlling an oxygen lance com prising an elevated support,elongated guide means for defining a substantially vertical path oftravel for the lance, the guide means being pivotally attached to thissupport to provide for swinging movement thereof in a horizontaldirection, a lifting mechanism mounted on these guide means, a guidecarriage restrained by the guide means for vertical reciprocationrelative thereto and a lance releasably affixed to the guide carriage.The lance moves with the guide carriage to which it is rigidly clampedand the movement of the guide carriage in the guide means offersaccurate control over the vertical positioning of the lance at any time.

In accordance with this invention, control of the lance is not hamperedby clamping means mounted either at the point at which the lance passesthrough the hood or otherwise independently mounted. The guide carriageand the guide ways or tracks in which the guide carriage travels serveto support the lance in a vertical Q C position against the eccentricforce from the weight of the hoses. These elements also oppose therotation and rocking of the lance under the buifeting action within theconverter While moving with the lance and continuously aligning andrigidly restraining it against vibration. Thus, there is no need forshutting off or cutting back the high velocity oxygen jet during thefrequent lance repositionings. As a result, a marked decrease in theblowing time is effected with consequent increase in converter tonnageoutput.

Also, since the mechanism supporting the lance is at a greater distancefrom the heat of the converter and since it is necessary to unclamp thelance from the guide carriage only when a new lance is to be inserted,there is a marked decrease in the maintenance costs incurred with thepresent device. Since the failure of hoodmounted clamps usually occursduring the blowing operation, the present improvement serves to decreasethe length of the blowing operation by the removal of theseinterruptions.

Other objects will cifically pointed out in greater description wherein:

FIGURE 1 is an elevational view showing the positioning of a preferredembodiment of this invention relative to the converter;

FIGURE 2 is a section taken on URE 1;

FIGURE 3 is an elevational view showing the guide be in part obvious andin part spedetail in the following line 2--2 of FIG- carriage-lanceconnection with the lower clamp pivoted to the open position, and

FIGURE 4 is a plan view showing the device of FIG- URE 1 swung to oneside to permit charging or tapping of the converter.

As shown in FIGURE 1, this invention may be advantageously used with theclosed bottom converter 11 in an oxygen steelmaking process. Thisinvention may also be used for the steelmaking process in other types offurnaces as, for example, in an open hearth furnace. Furnace orconverter 11 as illustrated herein is a conventional closed-bottomsteelmaking oxygen vessel having an outer shell 12 with a basicrefractory lining therefor composed of magnesia ramming mix 13 andtarbonded dolo-magnesia bricks 114.

Auxiliary equipment includes hood 16 for removing fumes and smoke fromconverter 11, and lance 17. Lance 17 is protected in a conventionalmanner by a water jacket, but for the sake of simplicity this structurehas not been shown.

In accordance with this invention, clamping means to continuouslyaccompany lance 17 is supplied, lance 17 being rigidly clamped to guidecarriage or cradle 18 by placing lance 17 in semi-cylindrical recess 19formed in cradle 18 and holding it in place by means of arcuate clamps21. Clamps 21 are pivotally supported by pro jections 22 which areformed or welded on the body of cradle 18. When each clamp 21 is swungabout pins 23 into the closed position, tongue-like projection 24 formedon the end of clamp 21 Swings between vertically spaced projections 26and 27. Wedge 28 is then forced through slot 29 in each projection 26,through opening 31 in tongue 2.4 and slot 32 in each projection 27 tourge arcuate clamp 21 forceably against lance 17. Since there is atleast a four-foot spread between the arcuate portions 21 the connectionbetween lance 17 and guide carriage 18 is a very rigid one.

Carriage 13 is adapted for vertical motion on structural steel guidetracks 33 by means of a series of flanged wheels 34 and 36, which run onrails 37 and 38. Although not shown, the weight of carriage 18 and lance17 can be partially offset by the use of a counter-balance. Guide tracks33 are afiixed in a substantially vertical position by means of struts39 and 41 which are pivotally connected to bearing brackets 42 and 43 bymeans of pins 44 and 46.

In the present illustration of the invention, carriage or cradle 18 isshown permanently mounted in tracks 33. However, it is but a simpleexpedient to permit carriage 18 to accompany lance 17 even while lance17 is not positioned for vertical motion. Thus, it may be convenient foreach spare lance to be supplied complete with a carriage permanently orsemi-permanently affixed thereto. A hinged portion of tracks 33 can beprovided having a hydraulic actuator to open it to permit entry ofcarriage 18 and thereafter to retain the hinged portion in closedposition pending removal of carriage 13.

During the charging and tapping operations of the converter 11, theentire arrangement of guide tracks 33, guide carriage or cradle 18, andlance 17 with the actuating mechanism therefor may be easily swung toone side or the other, the pivotal connections being so designed as topermit a swing of at least As is shown in FIGURE 1, the load of theentire assemblage is transmitted to structural steel column 47 supportedon girder 48 which is in turn supported on columns 49 and 51 placed atsome distance from the converter 11 to avoid danger from slag and metalspills at yard level. Thus, the entire support for lance 17 is elevatedor spaced a safe distance from converter 11. In addition to the aspectof safety, the proposed mounting of lance 17 requires less room on theoperating floor 52 and also at yard level.

The mechanism for lifting lance 17 together with carriage 1% is bestshown in FTGURE 4. A mounting plate 53 is provided as a support for theactuating mechanism including motor 5-1 coupled to motor reducer 56which in turn drives hoist drum 57 to raise and lower lance 17. Sincelance 17 is placed substantially at the center of gravity of carriage 18and chain yoke 58 picks up at the center of gravity of thecarriage-lance assembly, the arrangement shown permits an in-linelifting and lowering of lance 17 as well as in-line restraint andcontrol thereof. The driving mechanism being affixed to mounting plate53 moves with the guide tracks 33, carriage 18 and lance 17 to whicheverposition is assumed by pivoting the assembly about pins 44 and 46.Although not shown in the drawings, the guide tracks 33 areinterconnected by bracing members to keep them parallel to each otherand provide stiffer guide means.

In operation, once a new lance has been inserted into place in recess 19and clamped firmly thereto by clamps 21, the lance 17 is rigidly held insubstantially vertical position in spite of the weight of hoses 59exerting an eccentric force theeron. In preparation for the blowingoperation, once converter 11 has been charged, the entire assemblage oflance 17, carriage 18, and tracks 33 with the super-imposed liftingmechanism are swung over converter 11 and lance 17 is lowered throughopening 61 in hood 16 until the end of lance 17 is properly positionedover the bath. The lowering is, of course, effected by playing out wirecable 62 from the hoist drum 57 which lowers carriage 18 with lance 1'7rigidly affixed thereto. Whenever repositioning of lance 17 is requiredwithin converter 11, carriage 18 is moved carrying lance 17 with it tothe new position and remaining at all times rigidly fixed to lance 17firmly restraining it against the forces acting thereon to permitcontinuous blowing of the oxygen blast throughout the entirerepositioning operation.

The typical oxygen steelmaking blow heretofore has lasted about 15 to 30minutes, with as much as 3 or 4 minutes of this time being due to thelengthening of the blowing time as a result of oxygen in-put cessationor cutback during the repositioning of the lance. It may readily beappreciated that the present arrangement for continuously, rigidlyrestraining the lance 17 through the entire period of utilization of thelance, whereby no interruption of the oxygen blast need occur, willeffect additional economies in this new art of steelmaking. Although thepresent invention contemplates an in-line arrangement for the control ofthe lance, should it be desired to use a cluster of lances some smalleccentricity may be required to facilitate arranging the cluster.

In the present invention, the movement of lance 17 being limited to agiven path by carriage 18 and tracks 33, limit switches (not shown) mayreadily be employed to control the extent of downward movement ofcarriage 1S and lance 17. Also, in the event that wire cable 62 shouldbreak, a positive stop (not shown) to prevent the downward movement ofcarriage 18 and lance 17 may be provided. The present invention readilylends itself to the application of such a safety measure due to thefixed vertical path of movement. Free-falling lances have been known todrop into the bath still spewing oxygen resulting in the burning throughof the refractories and shell with consequent loss of metal and delaysin operations. The possibility of loss of life from such an accident issutliciently imminent to warrant the exercise of these safety measuresfor this reason alone.

Further, while the lance is inserted within the converter a build-up ofspatter occurs thereon. Such a build-up often becomes so large andunwieldy as to interfere with the blowing operations. In the prior artlance suspension systems (eccentric hang from wire cables) as thebuildup reached troublesome proportions it becomes necessary to removethe build-up material by pounding or by the use of a cutting torch. Thepresent device, on the contrary, lends itself to the installation of avibrator or rapping device (not shown) to apply sufiicient vibration tothe rigidly supported lance while in place to shake loose the materialstriking the lance before it becomes solidified, permanent build-up.

Although the present disclosure shows a lance installation in which theentire assembly of carriage, lance, guide track, and lifting mechanismare pivoted to the side, it may be seen that the lateral movement ofsuch entire assembly on a mono-rail, for example, is equally feasible.

It should be understood, of course, that the foregoing disclosurerelates to only a preferred embodiment of the invention and thatnumerous modifications or alterations may be made therein withoutdeparting from the spirit and the scope of the invention as set forth inthe appended claims.

What is claimed:

1. Apparatus for introducing a high velocity jet of fluid into a furnacecomprising in combination with an oxygen converter a support, a lancehaving a substantially rectilinear axis, vertically disposedinterconnected guide tracks, means for pivotally attaching said guidetracks to said support, a lifting mechanism supported by said guidetracks, a carriage mounted in said guide tracks for vertical movementrelative thereto, means on said carriage for rigidly afiixing the upperend of said lance to said carriage throughout repositionings of saidlance in said furnace during the blowing cycle, and meansinterconnecting said carriage with said lifting mechanism for verticalrepositioning of said carriage, lance and aflixing means along saidguide ways.

2. Apparatus for introducing fluid into a furnace comprising incombination, an oxygen converter, an elevated support, a pair ofvertical disposed interconnected guide ways offset from said support,means for pivotally mounting said guide ways on said support forswinging movement, a lifting mechanism mounted atop said guide ways, alance having a substantially rectilinear axis, a carriage rigidlyafiixed to the upper end of said lance throughout repositionings thereofin said furnace, said carriage being mounted in said guide ways forvertical reciprocation relative thereto, and means for suspending saidcarriage from said lifting mechanism with the center of gravity of thecarriage and lance assembly substantially in line with the applicationof force by said lifting mechamsm.

3. Apparatus for introducing a high velocity jet of fluid into a furnacecomprising in combination with an oxygen converter, an elongated lancehaving a substantially rectilinearaxis, an elevated substantiallyvertical support, a pair of rigidly interconnected vertically disposedtracks, means for pivotally mounting said tracks parallel to saidsupport, a lifting mechanism mounted atop said tracks and pivotabletherewith, a carriage having flanged wheels interposed between saidtracks for vertical rolling movement relative thereto, means on saidcarriage rigidly aifixing the upper end of said lance to said carriagethroughout repositionings thereof, the center of gravity of the carriageand lance assembly being substantially in line with the application offorce by said lifting mechanism.

References Cited in the file of this patent UNITED STATES PATENTS2,822,163 McFeaters Feb. 4, 1958 FOREIGN PATENTS 220,279 Great BritainFeb. 19, 1925 716,856 Great Britain Oct. 13, 1954 1,166,807 France June30, 1958 OTHER REFERENCES Jour. of Metals, pp. 396400, March 1953.

